Modification of Nias’ Cacao Pod Husk Cellulose through Carboxymethylation Stages by Using MAOS Method and Its Application as Li‐ion Batteries’ Biopolymer Electrolyte Membrane**

Abstract This research aimed to modify the Nias’ cacao pod husk cellulose by using Microwave‐assisted Organic Synthesis (MAOS) method to produce carboxymethyl cellulose and its application as lithium‐ion batteries’ biopolymer electrolyte membrane. There were two main stages of modification of Nias’ cacao pod husk cellulose i. e. cellulose alkalization and cellulose carboxymethylation process (etherification stage). Lithium‐ion batteries’ biopolymer electrolyte membrane was fabricated through the casting solution technique, where the blend of Methylcellulose/Carboxymethyl cellulose (MC/CMC) (80/20) (w/w) was complexed to 10 % (w/w) of lithium perchlorate. The determinations of functional groups, molecular structure, crystallinities, and thermal stability were conducted using Fourier Transform Infrared, Nuclear Magnetic Resonance, X‐Ray Diffraction, and Thermogravimetry Analysis, respectively. The lithium‐ion biopolymer electrolyte of the 10 % lithium perchlorate‐complexed MC/CMC (80/20) blend shows ionic conductivity, tensile strength/elongation at break, thermal stability are 5.91×10 −3 S cm −1 , 30.69 MPa/31.83 %, and 279.40–341.05 °C. Based on the results, the prepared biopolymer electrolyte of 10 % lithium perchlorate‐complexed MC/CMC (80/20) fulfills the separator (solid electrolyte) requirement for lithium‐ion battery application.